THE COMPLEX INTERPLAY OF SEX ALLOCATION AND SEXUAL SELECTION

Evolution ◽  
2012 ◽  
Vol 67 (3) ◽  
pp. 673-678 ◽  
Author(s):  
Isobel Booksmythe ◽  
Lisa E. Schwanz ◽  
Hanna Kokko
Keyword(s):  
Sexual Selection ◽  
Sex Allocation ◽  
Complex Interplay

scholarly journals Sex allocation conflict and sexual selection throughout the lifespan of eusocial colonies

2018 ◽  
Author(s):  
Piret Avila ◽  
Lutz Fromhage ◽  
Laurent Lehmann
Keyword(s):  
Resource Allocation ◽  
Sexual Selection ◽  
Evolutionary Biology ◽  
Sex Allocation ◽  
Colony Growth ◽  
Eusocial Insects ◽  
Dynamic Resource ◽  
Colony Ontogeny ◽  
Allocation Decisions ◽  
Allocation Strategies

AbstractModels of sex allocation conflict are central to evolutionary biology but have mostly assumed static decisions, where resource allocation strategies are constant over colony lifespan. Here, we develop a model to study how the evolution of dynamic resource allocation strategies is affected by the queen-worker conflict in annual eusocial insects. We demonstrate that the time of dispersal of sexuals affects the sex allocation ratio through sexual selection on males. Furthermore, our model provides three predictions that depart from established results of classic static allocation models. First, we find that the queen wins the sex allocation conflict, while the workers determine the maximum colony size and colony productivity. Second, male-biased sex allocation and protandry evolve if sexuals disperse directly after eclosion. Third, when workers are more related to new queens, then the proportional investment into queens is expected to be lower, which results from the interacting effect of sexual selection (selecting for protandry) and sex allocation conflict (selecting for earlier switch to producing sexuals). Overall, we find that colony ontogeny crucially affects the outcome of sex-allocation conflict because of the evolution of distinct colony growth phases, which decouples how queens and workers affect allocation decisions and can result in asymmetric control.

scholarly journals Sex‐allocation conflict and sexual selection throughout the lifespan of eusocial colonies

Evolution ◽  
2019 ◽  
Vol 73 (6) ◽  
pp. 1116-1132 ◽  
Author(s):  
Piret Avila ◽  
Lutz Fromhage ◽  
Laurent Lehmann
Keyword(s):  
Sexual Selection ◽  
Sex Allocation

scholarly journals Beyond sex allocation: the role of mating systems in sexual selection in parasitoid wasps

2014 ◽  
Vol 90 (2) ◽  
pp. 599-627 ◽  
Author(s):  
Rebecca A. Boulton ◽  
Laura A. Collins ◽  
David M. Shuker
Keyword(s):  
Sexual Selection ◽  
Sex Allocation ◽  
Mating Systems ◽  
Parasitoid Wasps

Reproductive strategies in hermaphroditic gastropods: conceptual and empirical approaches

2013 ◽  
Vol 91 (6) ◽  
pp. 367-381 ◽  
Author(s):  
Yumi Nakadera ◽  
Joris M. Koene
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Experimental Research ◽  
Reproductive System ◽  
Reproductive Strategy ◽  
Reproductive Strategies ◽  
Sex Allocation ◽  
Fitness Consequences ◽  
The Individual ◽  
Empirical Approaches

An individual optimizes its reproductive success by adopting a particular reproductive strategy. Studying the details of a reproductive strategy leads to an understanding of how sexual selection acts, as the former is the process via which the individual reproduces successfully. Hermaphroditic gastropods display a bewildering diversity of reproductive strategies, which may be due to their mode of gender expression, when compared with well-studied separate-sexed species. Extensive theoretical, observational, and experimental research has been conducted on this topic. However, despite our knowledge about the reproductive system of hermaphroditic gastropods, we still need to fill the gap between pre- and post-copulatory processes and reproductive success. Here, we review and propose conceptual and empirical approaches aimed at understanding reproductive strategies of hermaphroditic gastropods. In sum, our suggestions are (i) to focus on sex-biased traits, (ii) to take biologically reliable measurements at both the pre- and post-copulatory level that relate to reproductive success, and (iii) to examine the fitness consequences of biased sex allocation.

scholarly journals Sex allocation and investment into pre- and post-copulatory traits in simultaneous hermaphrodites: the role of polyandry and local sperm competition

2013 ◽  
Vol 368 (1613) ◽  
pp. 20120052 ◽  
Author(s):  
Lukas Schärer ◽  
Ido Pen
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Sex Allocation ◽  
Optimal Allocation ◽  
Recent Theory ◽  
Detailed Knowledge ◽  
Female Reproduction ◽  
Sexually Selected Traits ◽  
Simultaneous Hermaphrodites

Sex allocation theory predicts the optimal allocation to male and female reproduction in sexual organisms. In animals, most work on sex allocation has focused on species with separate sexes and our understanding of simultaneous hermaphrodites is patchier. Recent theory predicts that sex allocation in simultaneous hermaphrodites should strongly be affected by post-copulatory sexual selection, while the role of pre-copulatory sexual selection is much less clear. Here, we review sex allocation and sexual selection theory for simultaneous hermaphrodites, and identify several strong and potentially unwarranted assumptions. We then present a model that treats allocation to sexually selected traits as components of sex allocation and explore patterns of allocation when some of these assumptions are relaxed. For example, when investment into a male sexually selected trait leads to skews in sperm competition, causing local sperm competition, this is expected to lead to a reduced allocation to sperm production. We conclude that understanding the evolution of sex allocation in simultaneous hermaphrodites requires detailed knowledge of the different sexual selection processes and their relative importance. However, little is currently known quantitatively about sexual selection in simultaneous hermaphrodites, about what the underlying traits are, and about what drives and constrains their evolution. Future work should therefore aim at quantifying sexual selection and identifying the underlying traits along the pre- to post-copulatory axis.

scholarly journals Sex allocation and sexual conflict in simultaneously hermaphroditic animals

2009 ◽  
Vol 5 (5) ◽  
pp. 705-708 ◽  
Author(s):  
Lukas Schärer ◽  
Tim Janicke
Keyword(s):  
Sexual Selection ◽  
Theoretical Prediction ◽  
Experimental Test ◽  
Sexual Conflict ◽  
Sex Allocation ◽  
Theoretical Work ◽  
Theoretical Research ◽  
Sperm Donor ◽  
Simultaneous Hermaphrodites

Links between sex allocation (SA) and sexual conflict in simultaneous hermaphrodites have been evident since Charnov's landmark paper published 30 years ago. We discuss two links, namely the potential for sexual conflict over SA between sperm donor and recipient, and the importance of post-copulatory sexual selection and the resulting sexual conflict for the evolution of SA. We cover the little empirical and theoretical work exploring these links, and present an experimental test of one theoretical prediction. The link between SA and sexual conflict is an interesting field for future empirical and theoretical research.

scholarly journals Accessory male investment can undermine the evolutionary stability of simultaneous hermaphroditism

2009 ◽  
Vol 5 (5) ◽  
pp. 709-712 ◽  
Author(s):  
Nico K. Michiels ◽  
Philip H. Crowley ◽  
Nils Anthes
Keyword(s):  
Sexual Selection ◽  
Parameter Space ◽  
Sex Allocation ◽  
Evolutionary Stability ◽  
Evolutionary Stable Strategy ◽  
Implicit Assumption ◽  
Stable Strategy ◽  
Male Investment ◽  
Simultaneous Hermaphrodites

Sex allocation (SA) models are traditionally based on the implicit assumption that hermaphroditism must meet criteria that make it stable against transition to dioecy. This, however, puts serious constraints on the adaptive values that SA can attain. A transition to gonochorism may, however, be impossible in many systems and therefore realized SA in hermaphrodites may not be limited by conditions that guarantee stability against dioecy. We here relax these conditions and explore how sexual selection on male accessory investments (e.g. a penis) that offer a paternity benefit affects the evolutionary stable strategy SA in outcrossing, simultaneous hermaphrodites. Across much of the parameter space, our model predicts male allocations well above 50 per cent. These predictions can help to explain apparently ‘maladaptive’ hermaphrodite systems.

scholarly journals Exaggerated male legs increase mating success by reducing disturbance to females in the cave wētā Pachyrhamma waitomoensis

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180401 ◽  
Author(s):  
Murray Fea ◽  
Gregory I. Holwell
Keyword(s):  
Sexual Selection ◽  
New Zealand ◽  
Sexual Conflict ◽  
Mate Guarding ◽  
Opportunity Costs ◽  
Mating Effort ◽  
Sexually Dimorphic ◽  
Leg Length ◽  
Complex Interplay ◽  
Morphological Adaptations

Mate guarding is a widespread behaviour resulting from sperm competition and conflict over optimal remating rates. It is a key way in which males exhibit differential mating investment, and represents a complex interplay between mating effort, intrasexual competition, opportunity costs and sexual conflict. Nevertheless, although there are many examples of exaggerated male structures used to fight rivals, few animals have developed specialized male morphological adaptations for directly sheltering females from disturbance by non-rivals. Here we report on the use of sexually dimorphic, elongated male hind legs, which are used to guard females in the New Zealand cave wētā Pachyrhamma waitomoensis (Orthoptera: Rhaphidophoridae). We found that male hind legs alongside the female failed to deter rivals from accessing her or disrupting copulation. However, they did reduce the disturbance to females from other, non-rival animals such as juveniles and heterospecifics. Males with longer hind legs were more effective in reducing disturbance, and remained with females for longer. Longer guarding periods also led to higher numbers of matings between pairs. Models of males with artificially altered hind leg dimensions also showed a benefit to greater leg length, and artificially altering the disturbance rate to females also had a significant effect on pair duration. Our results indicate that nuisance disturbance to females may play an important role in driving sexual selection on male leg length and its exaggeration in this species.

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